<?php
class DES
{
    var $key;
    var $iv; //偏移量
  
    function DES($params)
    {
    	$key = $params['key'];
    	$iv = isset($params['iv']) ? $params['iv'] : 0;
        $this->key = $key;
        if($iv == 0)
        {
            $this->iv = $key;
        }
        else
        {
            $this->iv = $iv;
        }
    }
  
    //加密
    function encrypt($str)
    {
        $size = mcrypt_get_block_size ( MCRYPT_DES, MCRYPT_MODE_CBC );
        $str = $this->pkcs5Pad ( $str, $size );
  
        $data=mcrypt_cbc(MCRYPT_DES, $this->key, $str, MCRYPT_ENCRYPT, $this->iv);
        //$data=strtoupper(bin2hex($data)); //返回大写十六进制字符串
        return base64_encode($data);
    }
  
    //解密
    function decrypt($str)
    {
        $str = base64_decode ($str);
        //$strBin = $this->hex2bin( strtolower($str));
        $str = mcrypt_cbc(MCRYPT_DES, $this->key, $str, MCRYPT_DECRYPT, $this->iv );
        $str = $this->pkcs5Unpad( $str );
        return $str;
    }
  
    function hex2bin($hexData)
    {
        $binData = "";
        for($i = 0; $i < strlen ( $hexData ); $i += 2)
        {
            $binData .= chr(hexdec(substr($hexData, $i, 2)));
        }
        return $binData;
    }
  
    function pkcs5Pad($text, $blocksize)
    {
        $pad = $blocksize - (strlen ( $text ) % $blocksize);
        return $text . str_repeat ( chr ( $pad ), $pad );
    }
  
    function pkcs5Unpad($text)
    {
        $pad = ord ( $text {strlen ( $text ) - 1} );
        if ($pad > strlen ( $text ))
            return false;
        if (strspn ( $text, chr ( $pad ), strlen ( $text ) - $pad ) != $pad)
            return false;
        return substr ( $text, 0, - 1 * $pad );
    }
}
?>